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In order to get monthly NDVI image with max value from two 16 day-images, I used mosaick tool in ERDAS8.7 by choosing max function from "set overlap function" tool. But after doing this, when I see the value of output image using inquire curcior, the value is between 0-255. when I saw the layer info, the value of output image is within the range of NDVI image (-1 to 1). So What does it mean? What is the problem with output image? Can this way used to this process?

Many thanks

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This sounds remarkably like the situation described at… – whuber Jun 21 '11 at 4:17

What you have seen is the lookup table value. Open the attribute table and see the actual value or if you have Arc GIS. Open the file in Arc GIS (.img files can be opened in Arc Map) and apply new symbology. Try this.

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